The present invention relates to a manipulation device for a transmission apparatus for four-wheel drive motor vehicles, which can also be driven selectively by only the front wheels or rear wheels, and more particularly to a transmission apparatus having a sub-transmission combined with a main transmission and a clutch device for disconnecting the transmission of the power to either of the front or rear wheels, whereby the car may be driven in a high power four wheel driving range and an economical four wheel driving range.
Such an apparatus including the sub-transmission and the clutch device must be provided with a shift lever for manipulating the sub-transmission and another shift lever for manipulating the clutch device. This increases the difficulties in manipulation of the transmissions and clutch device.
In order to overcome these problems, there is disclosed in U.S. Pat. No. 4,170,273, a transmission apparatus for four-wheel drive motor vehicles in which a sub-transmission and clutch device can be manipulated by one shift lever to change the transmission speed of the sub-transmission and to convert the four-wheel drive into the two-wheel drive by the front wheels.
The manipulation device for the transmission apparatus comprises a shift rod axially slidably provided for shifting a clutch means for the sub-transmission, an actuating rod slidably provided in parallel with the shift rod, a shift lever connected to the actuating rod, a shift fork slidably mounted on the actuating rod and engaged with the clutch device, a first engaging means for causing the actuating rod and shift fork to come into the fixed engagement relation to each other within a first moving range of the shift lever, second engaging means provided for causing the actuating rod and shift rod to come into fixed engagement relation to each other within a second moving range of the shift lever adjacent the first moving range, and a stopper provided on a guide plate for stopping the shift rod and shift fork.
In such a device, the stopper secured to the guide plate is subjected to shifting forces through the shift rod and shift fork. As a result, the guide plate and cover thereof are liable to be damaged by the forces. Deformation of the cover causes the malfunction of the apparatus and/or oil leakage.